Reducing system.



M. F. WILLIAMS. REDUCINGSYSTEM. APPLICATION FILED mu 9, 1914.

Patented Nov. 10, 19M

2 SHEETS-SHEET 1.

M. F. WILLIAMS. REDUCING SYSTEM. APPLIGATION FILED MAY 9, 1914.

1,1 163777, Patented Nov. 10, 1914.

. t 2 SHEETSS HEET 2.

UNITED STATES] PatrEnT ornicn MILTON r. WILLIAMS, 0E T. oms. m sque; ASSIGNOR To W L A J T M censure Ann rULvEsIzEej come-1w. or $7 LOUI mlsspvm A CORPORATION OE MISSOURI,

e mi pme Y M- fSpeeificatitm oi? LettersPatent. Pa te1 1fed N v 10,1914 4 To all whom it may concern:

Be it known thatI, MIL'roNF. Winners,

1 a citizen of the United States, residing at the city ofSt. Louis, State of Missouri, have invented a certain new and usefuL Improve.-

ment in Reducing Systems, of which the following is a full, clearand exact def scription, such as will enable others skilled in the art to which appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which I Figure 1 is an illustration of my improved reducing system. Fig. 2 is a section of the form of grinder employed in my reducing system.v Fig. 3 is an illustration ofa modification of the system.

Myinvention'relates broadly to milling,

and specifically to a system of reducing li'ght materials, wherein is employed a grinder of .special design.

In the 'redu' tion of light substances such as grain, Wheat bran, screenings, middlinlgs, shorts, ship-stuff and other by-products commonly used as cattle feed, it is hard to get the reduced material through the grindrial .0

ing cage or concave of the grinder. This is due to the fact that the material being so light, it does not .fallthrough the interstices of the cage. @onsequently, the efficiency of the mill i's-greatly reduced by the fact that,

vide a reducing system which is absolutely dustless, all material which is discharged from the mill being handled in a closed systerhin which is provided means forse'paratingthe product and taking care ofthe dust.

My. system obviates the necessity of discharging the dust into the air as well as the alternate necessity of employing some sort of dust collector. T V

With the foregoing, and other objects, in

view, all of which will be obvious or hereinafter pointed out, it will beunderstood'that my invention contemplates a specialized form ofimill having a grinding chamber 1,

Application aiea m 9, 1,914. Serial n 837,445,

revoluble shaft which operate within the reduclngch mber 1, cooperatingwith a breaker plate and a foraminous cage 8. The foraminous cage 8 is interposed between the reducing chamber" 1 and the": discharge hopper 4:, and one of its purposes in the mill is to. determine the degree of fineness to which the material shall .be reduced, as the material is retainedto the action of the'beaters until it is sufficiently fine to pass through-the openings of the cage. I

The feed hopper 2 communicates with the grinding chamber 1 through a feed opening.

9. At one side of the feed hopper 2 is disposed an air inlet compartment 10 which communicates directly with the reducing chamber .through an air inlet opening 11. Air/is supplied to the air compartment 10 by; the pipe 12. "Communicating with the discharge hopper d is the discharge con "duit 1 1 which leads to, the eye of a centrifugal fan 15 carried on .the' machine .and' operated by the shaft 5.. From the discharge end of ran-15. a separator conduit 16 leads to a cycloneseparator 17. This is a device well .known in the art, which operates to break up the currents of air carrying the reduced material, permitting. the material to. be precipitated through the filling conduit 18 to any desired receptacle Ordinarily there is con siderable dust in the material which is not sufliciently heavy to be precipitated in the separator, and this e'scapes'with the aircurrents through a return conduit 19. This return conduit l9jcommunicates with the pipe 12 so that the air currents which leave the separator 17 are conducted to aircompartment 10, carrying with them such light dust as may be held in suspension.

It' will be understood that'the material to be reduced is fed to themill from the hopper 2 through the feed opening 9. The revolving beaters-6 first carry the material against the breaker plate 7- where it is crushed to a certain extent, andisubsequently to the cage 8 where it is reduced by the co.

operation of the heaters and the cage. Of d course, in the reduction of the light mate' rials enumerated, the material is carried around and around by the heaters and more or less of 'it will bein suspension in the g ndin h fi r a feed hopper 2-, and a discharge hopper 4. 5 carries rotary beaters6 Here it is that the 119 function of the air compartment 10 and the return of the air from the separator 17. thereto comes in. It is obvious that the action of the, fan 15 is to create considerable pressure in the system made up of the pipes 16, 19 and 12, and the separator 17, and-a considerable suction in the pipe 14 and discharge hopper 4.. The result is that-a con '8 into the hopper lfdue to the reduced pressure in the hopper. The action of this air pressure finding felief from reducing chamber 1 into discharge hopper 1, has .two important functions. In the first place, it forces the reduced material from the grindas soon as the material is. sufficiently fine to pass through the openings. Inthe sec- -terial on the. cage 8 and 0nd place, it tends to hold the unreduced maprevent its being carried around and around by the heaters. It is obvious that when so held the material will be reduced much more rapidly than when it is carried about by the beaters.

A very important feature of the device lies in the fact that the injected air is introduced into the grinding chamber independently of the unground material so that theair does not influence the feed of .the unground material into the mill. This prevents back pressure in the hopper 2, which back pressure would tend not only to hinder the entrance of the material into the-grinding chamber, but alsozmaterially reduce the force of the injected current of air and thereby decrease its efiiciency to force theground material through the cage and hold the unground material on the cage.

The course taken by the'air current is illustrated by the arrows in Fig. 2, and it I will be seen that its course is almost diametrically across the orbit of the beaters. Therefore, the point at which the air is'most eflicient is on that part of the cage which is opposite the breaker plate. This is the part of the cage upon which is most of the finely reduced material 'Therefore; itis obvious that the air currents are directed to where they can best be utilized in forcing thereduc'ed material through the cage. Furthermore, it is at this point"that the action jof the air currents is most effective in preventing the reduced-material being carried about by the beaters. When the dust which is introduced in the injected air. is thus brought into contact with the newly reduced material, a considerable portion of the dust is caught and held by the heavier reduced particles, with the result that a con-- siderable portion of the dust is preclpltated ingchamber through the foraminous cage along with the particles which so carry it, when the material is introduced into the a separator 17 that the return currents from the separator are always conducted back to the mill, it is Moreover, in view of the fact obvious that none of the dust will be-"per-' mitted to escape into the open air.

Notonly does this system render the operation dustless, and greatly increase the grinding efficiency of the mill, but it has a further valuable effect in keeping the mill cool, and in keeping the material cool. In

case the material is of a sort which reduces slowly, or has ,a tendency to pack, thereby preventing a sufficiently rapid flow of the air from reducing chamber 1 into the dis-.

charge hopper 1, it is obvious that too great a pressure might be produced in the conduits 16 and 1'9 and in the separator 17. To prevent this, I employ a special form of relief, which consists of a fine mesh plaited bag 20 which is connected to'the pipe19 by a relief pipe 21. A cut-off 22 is provided in pipe 21 by means of which communication between the pipe 19 and the bag 20 maybe opened or closed as occasions demand. The 1 fine meshed bag 20 will permit a certain amount of the-excess pressure in the system to exhaust therethrough, retaining the dust; such dust as collects in the bag 20 may be drawn ofi through a discharge valve 24 without. being scattered in the air.

Illustrated in Fig. 3 is another form of relief consisting of the pipe 25 which leads from pipe 19 back to the discharge hopper or to pipe 14:. This provides a by-pass through. which excessive pressure may es .cape when conditions in grinding chamber 1 are such as to prevent its sufficiently rapid passage through the cage, and furnishes the proper air supply. to the fan to enable the latterto keep the hopper. clear of reduced material. acut-off 26 by which the flow of air therethrough may be regulated. In the arrange ment illustrated in Fig. 1, in case the passage of air through the cage is not sufficient to accommodate fan'15, outside air may be admitted to pipe 14 bymeans of a valve 27 As illustrated in Figs. 1 and 2, a receptacle 13- may be placed in communication with pipe 12 adjacent its connection with the wall of the hopper. This receptacle is provided with 'a removable cap 13?; It often occurs that some metal or other refractory material becomes mixed with the material which is to be reduced, and is fed into the mill. When the rapidly revolving is ,thrown against the top of the grinding plate as shown in dotted lines Fig. 2, then back'i-nto the chamber 10 and into the pipe 12. The purpose of the receptacle 13 is to catch such material as may be ejected from the mill in this fashion as it slides back By-pass plpe 25 is provided with .hammers .strike this refractory material, it I I material down pipe 12. The removable cover 13 permits the receptacle being cleared of such as may be accumulated therein. The foreign material, which is usually in the form of metal or gravel, has suflicient momentum from the impact of the rapidly revolvinghammers, to carry it against the current of air emitted from chamber 10. is being reduced, how-' The material which ever, being of a light nature, does not have sufiicient momentum to make headwayagainst the air current, and hence, such material is not thrown into chamber 10 or the receptacle 13.

From the foregoing, it is obvious that my improved reducing system provides a means for greatly increasing the efficiency of the grinder, for preventing Wear of the mill by keeping it cool, for increasing the quality of theproduct by preventing its heating, and for greatly improving the process by rendering it dustless. I

I am aware that various changes and modifications may be made in the device illustrated and described, Without departing from the spirit of the invention or the scope of the appended claims.

What I claim is:

1. In a reducing system, of a separator, a grinder having a discharge hopper and-a grinding chamber separated by a foraminous cage, said chamber being provided With'a feed inlet and an air inlet,

the combination 7 rotary beaters cooperating with said cage in said grinding chamber, means for reducing the air pressure in said discharge hop-.

per and increasing the air pressure in said separator whereby to inject air into said grinding chamber through said air inlet; said air inlet being disposed to direct a current of air across the orbit of said heaters to said cage.

2. In a reducing system, a mill comprising a grinding chamber and a discharge hopper separated by a foraminous cage, rotary heaters cooperating with said cage in said grinding chamber, an air compartment having independent communication with said reducing chamber, means whereby air may be introduced under pressure to said air compartment, and a receptacle communicating with said air c01npartment for the reception of material projected 'thereinto from the grinding chamber.

3. In a reducing system, a mill comprising a grinding chamber, revolublebeaters operating therein, eating therewith, an aircompartment disposed adjacent the opening of said feed hopper, a conduit communicating With said air compartment and adapted to afford lodgment for material ejected fro said grindingchamber into said a1r compartment, and meansfor forcing alrinto the air compartment. i

In testimony whereof I hereunto afiixmy signature in the presence of two (witnesses, this 24th day. of April, 1914.

MILTON F. WILLIAMS.

Witnesses:

M. P. SMITH, C. S. BUTLER.

a feed hopper and a feed hopper comm'uni- 

